Pololu Blog (Page 6)
Welcome to the Pololu Blog, where we provide updates about what we and our customers are doing and thinking about. This blog used to be Pololu president Jan Malášek’s Engage Your Brain blog; you can view just those posts here.
Congratulations to the Bohlebots teams for winning all four open categories of the West German Robocup soccer 2017! Robocup soccer is a competition where two autonomous robots on each side play soccer in a walled arena. We covered them winning multiple times in the past on this blog. Their robots use Pololu 20D mm metal gearmotors and VNH5019 motor driver carriers.
Bohlebots junior team winning West German Robocup 2017 soccer open 1v1.
The Pololu Zumo Robot for Arduino is designed to be essentially a shield for the A-Star 32U4 Prime, Arduino Uno or Arduino Leonardo. Other Arduino boards that conform to the Arduino interface might work too. For example, customer Omar Elabd ported the ZumoMotors library to his Netduino 2! The Netduino is a 32-bit microcontroller board similar to Arduino that runs the .NET Micro Framework instead of using the Arduino environment.
He posted his code on GitHub and announced it on his blog. He is thinking of expanding his library to include ZumoBuzzer and ZumoReflectanceSensorArray libraries. The library is written in C#, which is exciting since I’m a C# programmer myself! If others would like to expand on these libraries, Omar is open to code contributions.
One of our customers, Jochen Alt, built a robot that balances on top of a ball by driving around on it with omni-wheels. Even better, he very thoroughly documented the project on GitHub! The robot uses a number of parts from Pololu including 37D mm metal gearmotors with encoders, stamped aluminum L-brackets for 37D mm metal gearmotors, and three VNH2SP30 motor driver carriers.
A good overview of the robot and the control system are on his Hackaday project page.
ToolParts is an online store in Seoul, South Korea, bringing our total number of distributors in Korea to five! They carry a selection of Pololu products including voltage regulators, motor drivers, and sensors.
Tronixlabs Australia is an online store located near Melbourne. They offer $5 flat rate shipping for all of Australia, and they do same-day shipping (a service we are also proud to offer at Pololu). They join our six other Australian distributors. Visit their Pololu products category to see what they carry.
See the full list of over 200 distributors to find one in your area.
A technical paper about hydrofoil design by members of the Cedarville University Solar Boat Team won a $1,000 Honorable Mention in the 2016 Mandles Prize for Hydrofoil Excellence from the International Hydrofoil Society. The boat they’ve been building uses a few Pololu Jrk 12v12 USB motor controllers to drive linear actuators that control the hydrofoil angle of attack which controls the boat’s flight. (Yes, flight: a hydrofoil boat uses wing-like hydrofoils that lift up the hull as they “fly” through the water.) They plan to enter this boat in the “Top Class” of the Dutch Solar Challenge. The “Top Class” provides entrants the opportunity to design every aspect of their solar-powered boat, which they will use in a series of sprint and endurance races over the course of five days. They also plan on racing in the Solar1 Solar Boat World Championship at the Yacht Club de Monaco.
Congratulations to Matthew Siracusa and William Rule who placed first in the Robot Arm competition of the Science Olympiad SE PA Regional Tournament last Wednesday! They used our custom laser cutting service to cut the base and structural components of the robot arm out of black ABS. We wrote about another one of Matthew’s projects on this blog when he made a 6-string banjo (that has a frame we also laser cut) as part of the 2014 Science Olympiad.
The Science Olympiad website has more information about the Robot Arm competition.
We’ve been offering quick-turn custom laser cutting service ever since “we” were just Candice and Jan operating a tabletop Epilog out of their home. Since then we’ve cut a wide assortment of customer designs including jewelry, engraved control panels, robot chassis, Christmas ornaments, and wedding invitations.
We started out mostly cutting acrylic, gradually moving into cutting a wider variety of plastics and wood. All along we’ve been improving our processes and increasing our capabilities by buying machines with bigger beds, better control systems, and more power. Without announcing it officially, we’ve been cutting metal for customers and ourselves over the past few years. For example, we cut our Basic Sumo Blade for the Zumo Chassis and the SMT stencils for our in-house electronics assembly. We’ve been refining our metal cutting processes and finding the best cut settings to minimize the chance of burring and dross, so most parts come out relatively clean and smooth to the touch.
The process quality has gotten to the level where we are comfortable announcing that metal laser cutting is generally available to customers!
You can see in the pictures above that laser-cut steel parts have a slight discoloration along the laser-cut edges caused by the chemical reaction that takes place when cutting. Depending on the steel type and whether the cuts are through the material, vector-etched line art, or raster-engraved filled-in areas, the discoloration is different (some tend to be brownish while others are a dark gray). We do not guarantee that parts will be free of blemishes; we ship the parts without any post processing, and we currently do not offer additional services such as deburring, tumbling, or bending.
As stocked materials (shown on our quote request page), we carry #304-2B stainless steel in 0.024″, 0.030″, 0.036″, 0.048″, 0.060", and mild steel in 0.030″ and 0.060″. We can arrange to use material you ship to us, but keep in mind that steel is the only metal we can cut. We cannot cut copper, brass, titanium, aluminum, or precious metals.
To get started on having your laser-cut steel parts cut, submit a quote request here.
@MarcisShadow is working on a project using a Raspberry Pi with a Pololu DRV8835 Dual Motor Driver Kit for Raspberry Pi to control a Celestron NexStar GoTo Mount, allowing web-based control of a telescope. He also uses a Pololu 5V Step-Up/Step-Down Voltage Regulator S7V7F5 connected to the motor driver to power the Raspberry Pi from the motor power supply.
The project is being documented in a multi-part series on DirtyAstro.com. Part 1 covers the electronics that come with the telescope mount, part 2 is about assembling and testing the DRV8835 driver kit and motors, part 3 tackles setting up the Raspberry Pi and using an SSH client (PuTTY) to connect to it remotely via a PC, and part 4 is about getting Node-Red running to program the Raspberry Pi graphically using a web interface from any machine on the network.
He is not finished with the project, but I have a couple of suggestions for him or anyone doing something similar: First, since his 12 V supply exceeds the maximum operating voltage of both the motor driver (11 V) and the regulator (11.8 V), I would recommend using different ones. Keep in mind that “wall-wart” DC power supplies, especially older transformer-based ones, can have a voltage significantly higher than the rated voltage. Second, a board running a full operating system is usually not great for timing-sensitive operations like counting encoder ticks. If it can’t keep up with the pulse rate, I would recommend using a secondary microcontroller for the encoders. One possibility would be to use the A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge, which incorporates a more appropriate 5.5 V – 36 V regulator, an Arduino-compatible microcontroller, and dual motor controllers.
See the full list of over 200 distributors to find one in your area.
This animated C-3PO replica, made by one of our customers, moves its eyes, arms, head, and—in true C-3PO fashion—tells tasteless jokes. The movements are animated by a Pololu Mini Maestro 18-channel USB servo controller. A Pololu RC switch with relay (controlled by the Maestro, not an RC transmitter) shuts off the power to the head to avoid servo humming noises. (You can achieve a similar result with most servos by not sending RC servo pulses, which a Maestro does when the servo target is zero.)
The customer’s C-3PO web page has more videos and extensive documentation on how the replica was built.